Evidence of the need for lubricating the flanges of rail wheels is audibly evident when a train travels around a curved section of track. The sound of the flanges of each wheel of the train rubbing against the sides of the rails is normally very audible as a high-pitched "squealing" sound. Of greater importance than the annoying sound this action produces is the wear on the rails and the wheels that results from the friction between these components. A common cure for friction between two rubbing surfaces and the wear that results is the application of a lubricant to the surfaces. However, in the case of rail wheels and tracks, care must be taken not to apply a lubricant to the interface between the crown of the rails and the rolling surfaces of the driving wheels of a locomotive, since friction is required at this interface to drive the locomotive forward, particularly on grades. Even if the lubricant is applied only to the flanges of the wheels, it may creep onto the rolling surfaces, where it is not needed or desired.
U.S. Pat No. 4,915,856 discloses a solid lubricant composition that can be formed into strands, blocks, or rods of lubricant. An applicator applies the solid lubricant to the rail wheels by rubbing it onto the flanges of the wheels. The solid lubricant transfers to the sides of the rails and from thence onto the side of following rail wheels, thereby lubricating the wheel flanges of substantially all of the cars in a train. Due to its high viscosity, the solid lubricant does not creep onto the adjacent surfaces of the wheels, where it is not desired. As a practical matter, the lubricant is typically applied to the wheel flanges of a locomotive at the front of a train.
One of the problems with the solid lubricant disclosed in the above-noted patent is that only a relatively limited amount of the material can conveniently be held in an applicator mounted adjacent to the wheel flange. The rate of application is sufficiently great that the solid lubricant supply is relatively quickly consumed. For short haul locomotives and light rail commuter trains, this limited quantity of the solid lubricant that is available to be applied is not such a problem, since the maintenance intervals on such trains are typically only a few days or weeks. Also, short haul trains are more readily available for servicing, during which the supply of solid lubricant in an applicator can readily be replenished. In contrast, long haul trains of the type that carry freight across the country, operate with a much longer maintenance interval, e.g., with scheduled maintenance occurring about every 92 days. Replenishing a solid lubricant block or rod in an applicator every few days is simply not practical on a long haul locomotive.
Ideally, it would be desirable to apply a lubricant to wheel flanges on the wheels of a locomotive at a rate that is determined by the rolling speed of the wheels. By controlling the rate of application as a function of train speed, it should be possible to meter the application of the lubricant to the wheel flanges in a manner that applies only the amount of lubricant required. Clearly, sufficient wheel flange lubricant to last for the entire normal maintenance interval cannot be contained within an applicator mounted under a locomotive. Instead, a different type of lubricant will be required, the lubricant must be stored in a compartment on the locomotive rather than under it, and the lubricant must be applied in a novel manner that ensures the wheel flanges are properly lubricated the entire time that the train is in operation. To ensure adequate lubrication is applied to transfer to the wheel flanges of other railcars in the train, it will be preferable to apply the lubricant to a plurality of wheel flanges on both sides of the trains, but from a single supply source, thereby simplifying the replenishment of the supply of lubricant, when needed.